If you can start Windows

System Restore is the easiest thing to try first. It can undo recent changes to your computer's system files that might have caused the problem. System Restore doesn't affect your personal files, such as email, documents, or photos.

Open System Restore

Open System Restore by clicking the Start button Picture of the Start button

. In the search box, type System Restore. Next, in the list of results, click System Restore.‌

If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

Recent updates from Microsoft might help fix the problem. Windows Update helps keep your computer up to date with the latest system updates and drivers. You can check Windows Update manually to help ensure you have the latest updates to Windows 7installed.

Check for updates

Open Windows Update by clicking the Start button

. In the search box, type Update, and then, in the list of results, click Windows Update.

In the left pane, click Check for updates, and then wait while Windows looks for the latest updates for your computer.

If you see a message telling you that updates are available, or telling you to review updates, click the message to view and select the updates.

In the list, click an update for more information. Select the check boxes for any updates that you want to install, and then click OK.

Click Install updates. Read and accept the license terms, and then click Finish if the update requires it.

If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

If you recently installed a hardware device, such as a sound card or video card, an incorrect or improperly installed device driver might be causing the problem.

Make sure you have the latest driver for the device installed. You can typically find drivers on the device manufacturer's website. Most drivers are self-installing—after you download them, you can usually just double-click the file to begin the installation.

If a driver isn't self-installing, follow these steps:

Update a driver

You must be logged on as an administrator for this procedure.

Open Device Manager by clicking the Start button

, clicking Control Panel, clicking System and Security, and then, under System, clicking Device Manager.

If you're prompted for an administrator password or confirmation, type the password or provide confirmation.‌

In the list of hardware categories, find the device that you want to update, and then double-click the device name.

Click the Driver tab, click Update Driver, and then follow the instructions.

If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

Safe mode starts Windows in a limited state. Only the basic files and drivers necessary to run Windows are started, which can help you troubleshoot software problems. For example, if a program runs as soon as you start Windows and can't be shut down, you can start Windows in safe mode, and then try to uninstall the program.

Start your computer in safe mode

Remove all CDs, DVDs, and other media from your computer, then restart it. Next, click the Start button

﻿, click the arrow next to the Shut Down button

, and then click Restart.

Do one of the following:

If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you'll need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.

If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to start in safe mode, and then press F8.

Some errors can be caused by problems with your computer's hard disk or random access memory (RAM), rather than problems with Windows or other software running on your computer.

Windows 7includes tools that can help identify and fix certain hardware-related errors. Serious errors might require you to contact the hardware manufacturer for support.

Check for hard disk errors

Open Computer by clicking the Start button

, and then clicking Computer.

Right-click the drive that you want to check, and then click Properties.

Click the Tools tab, and then, under Error-checking, click Check now.

If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

To automatically repair problems with files and folders that the scan detects, select Automatically fix file system errors. Otherwise, the disk check will report problems but not fix them.

To perform a thorough check, select Scan for and attempt recovery of bad sectors. This scan attempts to find and repair physical errors on the drive itself, and it can take much longer to complete.

To check for both file errors and physical errors, select both Automatically fix file system errors and Scan for and attempt recovery of bad sectors.

Click Start.

Check for memory problems

Open Memory Diagnostics Tool by clicking the Start button

, and then clicking Control Panel. In the search box, type Memory, and then click Diagnose your computer's memory problems.‌

If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

Choose when to run the tool. If you choose to restart your computer and run the tool immediately, make sure that you save your work and close all of your running programs. The Memory Diagnostics Tool will run automatically when you restart Windows.

If you can't start Windows at all

The following tools can help you uninstall or roll back software changes, repair Windows startup files, and restore your system from an earlier backup. If none of those suggestions fix the problem, you can reinstall Windows 7.

Several of the following tools are located on the System Recovery Options menu. This menu is preinstalled on your computer's hard disk, and is also on the Windows 7installation media.

When attempting to recover Windows:

If you use a Tablet PC or other computer with a touchscreen, you might need to connect a keyboard and mouse in order to use Startup Repair and the other tools in the System Recovery Options menu. For more information, see What are the system recovery options in Windows 7?

If Windows 7came preinstalled on your computer, your computer manufacturer might have included other recovery options. For more information, refer to the documentation that came with your computer, or go to the manufacturer's website.

Safe mode starts Windows in a limited state. Only the basic files and drivers necessary to run Windows are started, which can help you troubleshoot software problems.

For example, if a corrupted video card driver is preventing Windows from displaying, or if a program runs as soon as you start Windows and can't be shut down, you can start Windows in safe mode before the driver or program starts and then try to fix the problem.

Start your computer in safe mode

Remove all CDs, DVDs, and other media from your computer, then restart it. Click the Start button

, click the arrow next to the Shut Down button

, and then click Restart.

Do one of the following:

If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you'll need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.

If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to start in safe mode, and then press F8.

Startup Repair can detect and fix certain types of system problems that might prevent Windows from starting, such as missing or damaged system files.

Startup Repair is designed to start automatically if certain system problems are detected, but you can also run the tool manually.

Run Startup Repair using preinstalled recovery options

Remove all CDs, DVDs, and other media from your computer, and then restart it using the computer's power button.

Do one of the following:

If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.

If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to repair, and then press and hold F8.

On the Advanced Boot Options screen, use the arrow keys to highlight Repair your computer, and then press Enter. (If Repair your computer isn't listed as an option, then your computer doesn't include preinstalled recovery options, or your network administrator has turned them off.)

Select a keyboard layout, and then click Next.

On the System Recovery Options menu, click Startup Repair, and then follow the instructions.

Run Startup Repair using the Windows 7 installation disc or a USB flash drive, or a system repair disc

If your computer's system is severely damaged and you can't access the System Recovery Options menu on your computer, you can access it using the Windows 7installation disc or a USB flash drive, or using a system repair disc if you created one earlier.

To use this method, you need to restart your computer using the disc or USB flash drive.

Insert the Windows 7installation disc or USB flash drive, or a system repair disc, and then shut down your computer.

Restart your computer using the computer's power button.

If prompted, press any key and then follow the instructions that appear.

On the Install Windows page, or on the System Recovery Options page, choose your language and other preferences, and then click Next. If neither the Install Windows page nor the System Recovery Options page appear, and you're not asked to press any key, you might need to change some system settings. To learn how to do this, see Start your computer from a Windows 7 installation disc or USB flash drive.

You can use System Restore from the System Recovery Options menu. It's just like running System Restore normally, with one exception: System Restore can't create new restore points in this mode, so you can't undo a restore operation. However, you can run System Restore again and choose a different restore point, if one exists.

Run System Restore using preinstalled recovery options

Remove all CDs, DVDs, and other media from your computer, and then restart it using the computer's power button.

Do one of the following:

If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.

If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to repair, and then press and hold F8.

On the Advanced Boot Options screen, use the arrow keys to highlight Repair your computer, and then press Enter. (If Repair your computer isn't listed as an option, then your computer doesn't include preinstalled recovery options, or your network administrator has turned them off.)

Select a keyboard layout, and then click Next.

On the System Recovery Options menu, click System Restore, and then follow the instructions.

Run System Restore using the Windows 7 installation disc or a USB flash drive, or a system repair disc

If your computer's system is severely damaged and you cannot access the System Recovery Options menu on your computer, you can access it using the Windows 7installation disc or a USB flash drive, or using a system repair disc if you created one earlier.

To use this method, you need to restart your computer using the disc.

Insert the Windows 7installation disc or USB flash drive, or a system repair disc, and then shut down your computer.

Restart your computer using the computer's power button.

If prompted, press any key and then follow the instructions that appear.

On the Install Windows page, or on the System Recovery Options page, choose your language and other preferences, and then click Next. If neither the Install Windows page nor the System Recovery Options page appear, and you're not asked to press any key, you might need to change some system settings. To learn how to do this, see Start your computer from a Windows 7 installation disc or USB flash drive.

If you've used Windows Complete PC to create a system image backup as part of your backup plan, you can use the system image to restore your computer.

A system image is a copy of the partition on your hard disk that contains Windows. It also contains everything on that partition on the date you created the image, including Windows, your programs, and user data—such as documents, pictures, and music. You need to have created a system image beforehand to use this option.

When you restore your computer from a system image, the contents of your hard disk are replaced with the contents of the system image. This means that any changes you've made, programs you've installed, or files you've saved after the system image was created will likely be lost unless you have a recent backup of your data.

Restore from a system image using preinstalled recovery options

Remove all CDs, DVDs, and other media from your computer, and then restart it using the computer's power button.

Do one of the following:

If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.

If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to repair, and then press and hold F8.

On the Advanced Boot Options screen, use the arrow keys to highlight Repair your computer, and then press Enter. (If Repair your computer isn't listed as an option, then your computer doesn't include preinstalled recovery options, or your network administrator has turned them off.)

Select a keyboard layout, and then click Next.

On the System Recovery Options menu, click System Image Recovery, and then follow the instructions.

Restore from a system image using the Windows 7 installation disc or a USB flash drive, or a system repair disc

If you can't access the System Recovery Options menu on your computer, you can access it using the Windows 7installation disc or a USB flash drive, or using a system repair disc if you created earlier.

To use this method, you need to restart your computer using the disc.

Insert the Windows 7installation disc or USB flash drive, or a system repair disc, and then shut down your computer.

Restart your computer using the computer's power button.

If prompted, press any key and then follow the instructions that appear.

On the Install Windows page, or on the System Recovery Options page, choose your language and other preferences, and then click Next. If neither the Install Windows page nor the System Recovery Options page appear, and you're not asked to press any key, you might need to change some system settings. To learn how to do this, see Start your computer from a Windows 7 installation disc or USB flash drive.